Select Simple Pagination with the Next Result Key as next_page and Page Parameter as page.

You do not need to specify endpoint parameters or a data field as that information is included in the API url (emails.json).

Here's what your REST API input should look like at this point:

Under Advanced Settings, specify a header for the authentication key. The Parameter is Authorization, the Value is the authentication key from step 1, and the Type is Text:

Click Create Input. That's all there is to it. This is an example of how to retrieve the data in emails.json; however, other data is available. See the Salesloft API documentation for information about using the API: https://developers.salesloft.com/api.html.